The present invention relates generally to irradiation systems. The invention finds particular relation to an irradiation system in which an accelerator selectively supplies electron beams to either of a pair of processing chambers and will be described with particular reference thereto. It is to be appreciated that the invention will also find application in other radiant energy systems.
Irradiation systems are used for irradiating articles, such as foodstuffs, food utensils, medical devices, consumer goods, cosmetics, and waste products and their containers, with high energy electromagnetic radiation, such as an electron beam, x-rays, and microwaves, for various purposes including sterilizing or disinfecting such articles. Articles are also irradiated in conjunction with cross polymerization of plastics and other material.
Heretofore, articles have been irradiated by utilizing a treatment application system that includes a radiation source, a plurality of article carriers, and a process conveyor for transporting the article carriers past the radiation source. The radiation source is mounted, for example, perpendicular to the conveyor along an approximately horizontal axis to irradiate the articles as they are transported past the radiation source.
In some systems, the article carriers are suspended from a power-and-free overhead conveyor. After the article carrier has been transported past the radiation source, some systems rotate the article carrier 180xc2x0 and transport the reoriented article carrier past the radiation source again. In this manner, the irradiation during the initial transportation past the radiation source is symmetrically balanced. In one prior system, the article carrier is suspended from the power-and-free conveyor track at both its leading and trailing ends. It is reoriented by diverting the leading end to an unpowered branch track that loops off to one side and then rejoins the main track. The trailing end moves along the powered main track so that the trailing end takes the lead and pulls the diverted end from the branch track to the main track in a trailing position.
Other systems utilize a radiation source, article carriers, and several inverted conveyor systems (i.e., the chain is on the bottom of the conveyor). The conveyor system includes transport conveyors for loading/unloading, a process conveyor, and a stabilizing conveyor to stabilize movement of the article carrier. The transport conveyor transfers the carrier directly to the process conveyor.
However, existing systems do not provide for irradiating at different energy levels or in two different processing chambers using one centrally located accelerator.
Accordingly, it has been considered desirable to develop a new and improved irradiation system which would overcome the foregoing difficulties and others and which would produce better and more advantageous overall results.
In accordance with one aspect of the present invention, an irradiation system comprises a radiation source, a first processing chamber positioned adjacent the radiation source, and a second processing chamber positioned adjacent an opposite side of the radiation source. The first processing chamber and the second processing chamber are positioned opposite each other. The radiation source selectively feeds an electron beam to one of the processing chambers and selectively feeds an electron beam of a different energy level to the other of the processing chambers.
The radiation source provides an electron beam of a high energy level, such as 10 MeV, to the first processing chamber. The radiation source provides a low energy level electron beam, such as 5 MeV, to the second processing chamber. The 10 MeV and 5 MeV beams are not provided simultaneously. The radiation source further includes a rotary particle accelerator and beam bending magnets which change the direction of an electron beam generated by the particle accelerator between the first processing chamber and the second processing chamber when selected.
A conveying system is provided for transporting article carriers through the first processing chamber. The conveying system comprises a code system for tracking articles as they are transported through the first processing chamber.
A reel-to-reel system is provided for feeding articles of indefinite length through the second processing chamber.
One advantage of the present invention is that it reduces accelerator costs when there is a need for two accelerators (5 MeV and 10 MeV) at a single location.
Another advantage of the present invention is that it provides multiple energy levels, such as a 10 MeV electron beam and a 5 MeV electron beam.
Yet another advantage of the present invention is that it reduces reconfiguring time and cost for processing different types of articles by quick switching between 10 MeV treatment and the 5 MeV treatment.
Still another advantage of the present invention is that it reduces down time due to set up and preparation.
Yet still another advantage of the present invention is that medical products and food can be processed in the 5 MeV vault.
Still other advantages and benefits of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.